The present application relates to the field of medical imaging apparatus, and more particularly, to a cradle drive mechanism, a table having such cradle drive mechanism and a patient imaging and carrying apparatus having such table.
Generally, a patient can be scanned and imaged by a variety of imaging techniques in order to make diagnosis Such imaging techniques can include magnetic resonance imaging (MRI), computer tomography (CT), X-ray imaging, positron emission tomography (PET) and the like. A patient imaging and carrying apparatus employing such imaging techniques generally includes a movable table so as to carry and position the patient accurately.
As shown in FIG. 1, a patient imaging and carrying apparatus employing the magnetic resonance imaging technique usually includes the following three portions: a table 21, an imaging system 22 and a rear pedestal 23. In this apparatus, the imaging system 22 is a magnetic resonance imaging system. The table 21 is movable, in order to get close to the imaging system 22. The table 21 can also move up and down so that the vertical position of the patient can be adjusted. The table 21 includes a cradle 24, and the cradle 24 can move relative to the table 21 in order to carry the patient into the magnet bore of the imaging system 22. When the front part of the cradle 24 passes through the magnet bore and moves out of the magnet bore, a bridge 25 within the imaging system 22 can support the cradle 24. The rear pedestal 23 includes a cradle traction element 26 and a drive motor 27 thereon The drive motor 27 can drive the cradle traction element 26. The cradle traction element 26 can pass through and protrude out of the magnet bore to couple to the cradle 24, thereby to drive the cradle 24 to move.
The structure of such apparatus has the following problems. The rear pedestal 23 requires a rather larger room. It is also not convenient for the physician to operate on the patient while performing imaging for diagnosis due to the rear pedestal 23.
Since the functions of the rear pedestal 23 are to support the cradle 24 moving into the magnet bore and to drive the cradle 24 to move, a novel cradle drive mechanism must be proposed in order to remove the rear pedestal 23.
There has been a two layered cradle drive mechanism in the prior art, which has an additional intermediate cradle between the table and the cradle. Generally, such two layered cradle drive mechanism employs two drive motors to drive the intermediate cradle and the cradle, respectively, so that the cradle can achieve a large travel range. However, because the mechanism employs two drive motors, this apparatus has high cost and complicated structure; besides, the movement accuracy of the cradle is low.
Japanese Patent Application Publication No. 2010-57700A discloses an improved two layered cradle drive mechanism. As shown in FIG. 2, the cradle drive mechanism includes a drive motor 5, a transmission belt 6, an auxiliary cradle 3 and an endless transmission belt 2. The drive motor 5 can drive the transmission belt 6 by a shaft 9 and two belt wheels 12 fixed on the table base 4. The auxiliary cradle 3 can be supported by a support 16 fixed on the transmission belt 6 and can move with the transmission belt 6. Two belt wheels 13 are fixed on the auxiliary cradle 3. A fastener 14 is fixed on the cradle 1 and is fixed on one side of the endless transmission belt 2, and a fastener 15 is fixed on the table base 4 and is fixed on the other side of the transmission belt 2. Therefore, when the auxiliary cradle 3 is moving, the transmission belt 2 is forced to rotate and drives the cradle 1 to move with it. In the cradle drive mechanism shown in FIG. 2, the cradle 1 can be regarded as an upper layer cradle, and the auxiliary cradle 3 can be regarded as a lower layer cradle, thereby forming the two layered cradle drive mechanism. Though only one drive motor 5 is employed in such a two layered cradle drive mechanism, two transmission belts are employed to drive the upper layer cradle and the lower layer cradle respectively. Because there may be a motion asynchronization between the transmission belts and the belt wheels, the movement accuracy of the cradle 1 is still lower.
Therefore, there is a need for a cradle drive mechanism, a table and a patient imaging and carrying apparatus that can overcome the above mentioned disadvantages.